Japan used the opium trade of Shanghai's major dealer to prop up the value of its military currency in occupied China during the war, according to a leading expert on China's wartime economy, citing a former secret document.
The latest finding in the document on the Japanese-run opium firm Hung Chi Shan Tang, now kept in the National Diet Library, reveals Japan used opium to gain economic hegemony over Chiang Kai-shek's yuan-based legal tender in the 1940s, using it to bolster the military "gunpyo" scrip, said Hideo Kobayashi, a professor at Waseda University in Tokyo.
"It has been said that opium may have been used to support the value of (Japan's) military currency, but this is the first glimpse at how the system worked and the exact amount (of opium involved)," said Kobayashi, author of a number of books on the war Japan waged and the economy of occupied China.